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5565b8e0ad
[BACKGROUND]
In theory init_btrfs_fs() and exit_btrfs_fs() should match their
sequence, thus normally they should look like this:
init_btrfs_fs() | exit_btrfs_fs()
----------------------+------------------------
init_A(); |
init_B(); |
init_C(); |
| exit_C();
| exit_B();
| exit_A();
So is for the error path of init_btrfs_fs().
But it's not the case, some exit functions don't match their init
functions sequence in init_btrfs_fs().
Furthermore in init_btrfs_fs(), we need to have a new error label for
each new init function we added. This is not really expandable,
especially recently we may add several new functions to init_btrfs_fs().
[ENHANCEMENT]
The patch will introduce the following things to enhance the situation:
- struct init_sequence
Just a wrapper of init and exit function pointers.
The init function must use int type as return value, thus some init
functions need to be updated to return 0.
The exit function can be NULL, as there are some init sequence just
outputting a message.
- struct mod_init_seq[] array
This is a const array, recording all the initialization we need to do
in init_btrfs_fs(), and the order follows the old init_btrfs_fs().
- bool mod_init_result[] array
This is a bool array, recording if we have initialized one entry in
mod_init_seq[].
The reason to split mod_init_seq[] and mod_init_result[] is to avoid
section mismatch in reference.
All init function are in .init.text, but if mod_init_seq[] records
the @initialized member it can no longer be const, thus will be put
into .data section, and cause modpost warning.
For init_btrfs_fs() we just call all init functions in their order in
mod_init_seq[] array, and after each call, setting corresponding
mod_init_result[] to true.
For exit_btrfs_fs() and error handling path of init_btrfs_fs(), we just
iterate mod_init_seq[] in reverse order, and skip all uninitialized
entry.
With this patch, init_btrfs_fs()/exit_btrfs_fs() will be much easier to
expand and will always follow the strict order.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
183 lines
6 KiB
C
183 lines
6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_COMPRESSION_H
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#define BTRFS_COMPRESSION_H
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#include <linux/sizes.h>
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struct btrfs_inode;
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/*
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* We want to make sure that amount of RAM required to uncompress an extent is
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* reasonable, so we limit the total size in ram of a compressed extent to
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* 128k. This is a crucial number because it also controls how easily we can
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* spread reads across cpus for decompression.
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*
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* We also want to make sure the amount of IO required to do a random read is
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* reasonably small, so we limit the size of a compressed extent to 128k.
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*/
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/* Maximum length of compressed data stored on disk */
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#define BTRFS_MAX_COMPRESSED (SZ_128K)
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static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
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/* Maximum size of data before compression */
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#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
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#define BTRFS_ZLIB_DEFAULT_LEVEL 3
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struct compressed_bio {
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/* Number of outstanding bios */
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refcount_t pending_ios;
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/* Number of compressed pages in the array */
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unsigned int nr_pages;
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/* the pages with the compressed data on them */
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struct page **compressed_pages;
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/* inode that owns this data */
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struct inode *inode;
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/* starting offset in the inode for our pages */
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u64 start;
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/* Number of bytes in the inode we're working on */
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unsigned int len;
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/* Number of bytes on disk */
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unsigned int compressed_len;
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/* The compression algorithm for this bio */
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u8 compress_type;
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/* Whether this is a write for writeback. */
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bool writeback;
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/* IO errors */
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blk_status_t status;
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union {
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/* For reads, this is the bio we are copying the data into */
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struct bio *orig_bio;
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struct work_struct write_end_work;
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};
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};
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static inline unsigned int btrfs_compress_type(unsigned int type_level)
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{
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return (type_level & 0xF);
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}
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static inline unsigned int btrfs_compress_level(unsigned int type_level)
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{
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return ((type_level & 0xF0) >> 4);
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}
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int __init btrfs_init_compress(void);
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void __cold btrfs_exit_compress(void);
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int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
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u64 start, struct page **pages,
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unsigned long *out_pages,
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unsigned long *total_in,
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unsigned long *total_out);
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int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
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unsigned long start_byte, size_t srclen, size_t destlen);
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int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
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struct compressed_bio *cb, u32 decompressed);
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blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
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unsigned int len, u64 disk_start,
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unsigned int compressed_len,
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struct page **compressed_pages,
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unsigned int nr_pages,
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blk_opf_t write_flags,
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struct cgroup_subsys_state *blkcg_css,
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bool writeback);
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void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
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int mirror_num);
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unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
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enum btrfs_compression_type {
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BTRFS_COMPRESS_NONE = 0,
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BTRFS_COMPRESS_ZLIB = 1,
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BTRFS_COMPRESS_LZO = 2,
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BTRFS_COMPRESS_ZSTD = 3,
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BTRFS_NR_COMPRESS_TYPES = 4,
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};
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struct workspace_manager {
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struct list_head idle_ws;
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spinlock_t ws_lock;
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/* Number of free workspaces */
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int free_ws;
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/* Total number of allocated workspaces */
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atomic_t total_ws;
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/* Waiters for a free workspace */
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wait_queue_head_t ws_wait;
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};
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struct list_head *btrfs_get_workspace(int type, unsigned int level);
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void btrfs_put_workspace(int type, struct list_head *ws);
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struct btrfs_compress_op {
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struct workspace_manager *workspace_manager;
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/* Maximum level supported by the compression algorithm */
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unsigned int max_level;
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unsigned int default_level;
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};
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/* The heuristic workspaces are managed via the 0th workspace manager */
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#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
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extern const struct btrfs_compress_op btrfs_heuristic_compress;
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extern const struct btrfs_compress_op btrfs_zlib_compress;
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extern const struct btrfs_compress_op btrfs_lzo_compress;
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extern const struct btrfs_compress_op btrfs_zstd_compress;
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const char* btrfs_compress_type2str(enum btrfs_compression_type type);
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bool btrfs_compress_is_valid_type(const char *str, size_t len);
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int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
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int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
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u64 start, struct page **pages, unsigned long *out_pages,
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unsigned long *total_in, unsigned long *total_out);
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int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
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int zlib_decompress(struct list_head *ws, unsigned char *data_in,
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struct page *dest_page, unsigned long start_byte, size_t srclen,
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size_t destlen);
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struct list_head *zlib_alloc_workspace(unsigned int level);
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void zlib_free_workspace(struct list_head *ws);
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struct list_head *zlib_get_workspace(unsigned int level);
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int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
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u64 start, struct page **pages, unsigned long *out_pages,
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unsigned long *total_in, unsigned long *total_out);
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int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
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int lzo_decompress(struct list_head *ws, unsigned char *data_in,
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struct page *dest_page, unsigned long start_byte, size_t srclen,
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size_t destlen);
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struct list_head *lzo_alloc_workspace(unsigned int level);
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void lzo_free_workspace(struct list_head *ws);
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int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
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u64 start, struct page **pages, unsigned long *out_pages,
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unsigned long *total_in, unsigned long *total_out);
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int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
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int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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struct page *dest_page, unsigned long start_byte, size_t srclen,
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size_t destlen);
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void zstd_init_workspace_manager(void);
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void zstd_cleanup_workspace_manager(void);
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struct list_head *zstd_alloc_workspace(unsigned int level);
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void zstd_free_workspace(struct list_head *ws);
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struct list_head *zstd_get_workspace(unsigned int level);
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void zstd_put_workspace(struct list_head *ws);
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#endif
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